Understanding Wine Spoilage and Telling When It Has Gone Bad

Have you ever encountered the vinegar-like smell commonly known as Vin egre, or bad wine? If there is a hint of vinegar smell or taste, the wine is indeed off or has gone bad. This is often the first sign you might notice when opening a bottle, making it essential for sommeliers to carefully sniff the cork.

Identifying Spoiled Wine

A quick sniff of the cork is sufficient: if there is a noticeable vinegary smell, it indicates that the cork has leaked and air has entered the bottle. This can happen if the wine has been improperly stored or if the cork is damaged or deteriorated.

If the wine contains sediment in the bottom of the bottle or has begun to taste like vinegar, these are clear signs that the wine has spoiled. For wines sealed with a screw top, the risk of spoilage is generally lower, but proper storage is still necessary. If the cork smells of mushrooms, the wine is likely bad, as this can be a sign of microbial contamination.

When Can Wine Still Be Enjoyed Yet Considered Spoiled?

It is important to note that wine can be considered spoiled not just because it has gone off, but also if it no longer meets the preferences of the drinker. Sometimes, wine can turn into useful vinegar if left open for a couple of months, but this is not typically considered a desirable transformation for most wine enthusiasts.

Wine contains ethanol, a toxic substance that can lead to various social issues. Despite this, alcohol acts as a preservative, and up until the last century, most wines were either sweet or oxidized. These flavors were generally what the average wine drinker appreciated.

To properly assess a wine, pour a small amount into a clear glass and tilt the glass to examine the wine through a thin layer. A brownish color usually indicates oxidation, which is generally undesirable. While smell can be unreliable, some wines, especially European-style reds, may naturally have a barnyard odor that may only develop over time.

Common Wine Defects

Here are some common defects that are often encountered in wine:

1. Corked Wine

This defect is characterized by an unpleasant, pencil-shavings-like odor and taste, lacking in fruitiness and being sharp and thin. It usually results from a flawed or deteriorated cork, leading to microbial infection. This is often referred as "corked."

2. Reduction

Reduction in wine often results from insufficient oxygen during the winemaking process, leading to a hydrocarbon-like aroma—a smell akin to cooking gas. This defect does not improve with airing.

3. Malolactic Fermentation After Bottling

This is a bacterial fermentation that can occur after bottling, causing natural fizziness and an unpleasant soapy off-taste in red wines. Sulfur dioxide is supposed to prevent this, but sometimes its use is inadequate.

4. Oxidation

Oxidation can result in stale wine and edge-browning, often from servers pouring from bottles that have been open too long. This is particularly common in restaurant wines served by the glass. Refusing such oxidized wine is perfectly acceptable.

5. Volatile Acidity

This defect is characterized by an acetic odor, often found in otherwise sound wines, leading to a so-called "vinegar" taste. It results from another bacterial infection that occurs during winemaking.

Proper Wine Storage

When purchasing wine, especially on a hot summer day, avoid placing bottles in the trunk of your car, even for a short trip home. Excessive heat can accelerate aging and spoilage. Proper storage, such as in a cool, dark place, is essential to preserve the quality of wine.

By understanding the signs of wine spoilage and taking proper care of your wine, you can ensure that you continue to enjoy the best possible flavor and quality in every bottle.